Would love to have a quick way to use splines, or objects to modify a model on the fly. Best example to explain it is a tool that was created for BLENDER called "Boxcutter". Brilliant idea and I wish our devs could create and integrate this into 3ds Max and stay on the forefront of CG modeling.
Boxcutter example -
https://boxcutter-manual.readthedocs.io/en/latest/?fbclid=IwAR2VzVmch4f5Feu_n7OnarNf5-J6l-jbKq4S8Fde...